The present invention relates generally to the manufacture of heat transfer apparatus and, in particular, to methods and apparatus for assembling vessels or vessel internals such as substantially cylindrical, cage-like structures made of tubular components, in pie-shaped, longitudinal segments while in a horizontal or vertical position utilizing longitudinal or circumferential attachments.
Certain types of heat transfer apparatus comprise tubular, fluid conveying structures arranged in specified geometries. During operation, these tubular structures convey a cooling fluid, such as water, steam or mixtures thereof through an interior portion of the tubes, while hot gases are conveyed around outside surfaces of the tubes. Heat from the hot gases is conveyed through the tube walls into the cooling fluid which is conveyed to other locations or devices, such as turbines or other devices, for use. The properties of the hot gases, which include but are not limited to their temperature, chemical constituents, corrosion potential, emissivity, and their slagging and/or fouling potential, influence the geometries, spacing, arrangement, materials, and sizing of the tubular structures to a great degree.
The construction of radiant synthesis gas (syngas) cooler apparatus used to contain and cool the synthesis gas produced by a coal gasification process such as an Integrated Gasification Combined Cycle (IGCC) power plant is a classic example of one type of heat transfer apparatus where the properties of the hot gases influence the tubular, fluid conveying structures provided within the syngas cooler. These syngas coolers are typically long, substantially cylindrical pressure vessels which contain within an external shell of the vessel a specific arrangement of tubular, fluid conveying structures which are used to extract heat from the hot synthesis gas and when erected may be on the order of 100 feet tall or more, and have a diameter on the order of 20 feet or more.
The tubular, fluid conveying structures within such syngas coolers typically comprise a substantially cylindrical, cage-like structure within which may be located additional tubular structures known as division or platen walls. The cage-like structure may be substantially cylindrical along a central portion thereof, and provided with inlet and outlet structures which may be frustoconical or tapered to admit and exhaust, respectively, the hot synthesis gases into the cage-like structure during operation. Headers and/or manifolds are generally provided at both the inlet and outlet structures to provide common locations for the delivery and removal of the fluid conveyed through the cage-like structure.
While the headers and manifolds may have substantial diameters and wall thicknesses, the majority of the cage-like, tubular structure is comprised of long, slender tubes on the order of 2″ outside diameter (O.D.). These tubes are generally straight, and only bent as necessary to accommodate the aforementioned inlet and outlet structures. The substantially cylindrical walls of the cage-like structure are formed of these tubes and welded to one another by means of a membrane structure as is known to those skilled in the boiler arts. Furthermore, while the division or platen walls which may be provided in an interior portion are generally planar structures comprised of membraned tubes, they may have other shapes, such as an angled or “dog leg” configuration, and they may not be attached to the substantially cylindrical walls or to the inlet and outlet structures and thus the entire cage-like, tubular structure is not a rigid, easily handled structure nor can it be easily manipulated.
It is thus clear that development of an efficient technique for manufacturing and transporting heat transfer devices comprising substantially cylindrical, cage-like structures made of long, slender tubular components would be welcomed by industry.